The bug causes Safari to retain records of all sites you've visited in the form of "favicon" icons (the ones that appear in the URL field and bookmarks) with accompanying URLs.

As of this week's OS X Yosemite 10.10.3 build 14D98g, the latest update to be released to developers, Safari is still saving these easily accessible nuggets for every page you visit, the site says.

Hopefully this is something that Apple addresses soon, although the fact that this has been a known issue for years is not a good sign.

For now the best thing you can do is to trash the "WebpageIcons" database in the Safari folder of your system's Library directory, clear your history and website data within Safari, and be aware that your web browsing is never truly private.